There has been known a communication technology which uses a very wide band referred to as UWB (Ultra Wide Band) (refer to Patent Document 1 (Japanese Laid-Open Patent Publication (Kokai) No. 2003-179577), for example). The UWB uses frequency hopping which changes the frequency used for respective symbols.
It is also widely known that an EVM (Error Vector Magnitude) and a phase error of a UWB signal are measured in association with the time axis.
FIG. 11(a) shows a graph displaying the EVM of the UWB signal in association with the time axis, and FIG. 11(b) shows a graph displaying the phase error of the UWB signal in association with the time axis. It should be noted that the time axis is assigned to the horizontal axis and time is represented as symbols (symbols 25 to 31 are shown) in FIGS. 11(a) and 11(b). According to the graphs shown in FIGS. 11(a) and 11(b), it is possible to know an EVM and a phase error at a certain time point (symbol).
However, it is not possible to know to which frequency band an EVM or a phase error corresponds to according to the graphs shown in FIGS. 11(a) and 11(b). For example, it is assumed that the UWB signal uses a first frequency band for symbols 25, 28, 31, . . . , uses a second frequency band for symbols 26, 29, 32, . . . , and uses a third frequency band for symbols 27, 30, 33, . . . . It is not possible to determine which of the first, second, or third frequency band an EVM or a phase error corresponds to by just viewing the graphs shown in FIGS. 11(a) and 11(b).
It is therefore an object of the present invention to display which frequency band physical quantities (such as the EVM and the phase error) of a signal using the frequency hopping correspond to.